Rotatable cartridge for processing and analyzing a biological sample

ABSTRACT

An automatic analyzer cartridge, spinnable about a rotational axis, has fluid and aliquoting chambers, a metering chamber connected to a vent that is nearer to the rotational axis than the metering chamber, first and second ducts connecting the fluid and aliquoting chambers, and the metering and aliquoting chambers, respectively. Metering chamber side walls taper away from a central region, wherein capillary action next to the walls is greater than in the central region. Fluid flows to the metering chamber using capillary action via the second duct that has an entrance and exit in the aliquoting and metering chambers, respectively; the exit being closer to the rotational axis than the entrance. A downstream fluidic element connects to the metering chamber via a valve. A fluidic structure receives and processes a biological sample into the processed biological sample and has a measurement structure that enables measurement of the processed biological sample.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/EP2015/062337, filed Jun. 3, 2015, which claims priority to Europeanpatent application No. EP14171424.6, filed Jun. 6, 2014.

TECHNICAL FIELD

The inventive embodiments disclosed herein relate to analytical testdevices for biological samples, in particular to the design and use ofrotatable cartridges for performing a measurement of a biologicalsample.

BACKGROUND AND RELATED ART

Two classes of analysis systems are known in the field of medicalanalysis: wet analysis systems, and dry-chemical analysis systems. Wetanalysis systems, which essentially operate using “wet reagents” (liquidreagents), perform an analysis via a number of required step such as,for example, providing a sample and a reagent into a reagent vessel,mixing the sample and reagent together in the reagent vessel, andmeasuring and analyzing the mixture for a measurement variablecharacteristic to provide a desired analytical result (analysis result).Such steps are often performed using technically complex, large,line-operated analysis instruments, which allow manifold movements ofparticipating elements. This class of analysis system is typically usedin large medical-analytic laboratories.

On the other hand, dry-chemical analysis systems operate using “dryreagents” which are typically integrated in a test element andimplemented as a “test strip”, for example. When these dry-chemicalanalysis systems are used, the liquid sample dissolves the reagents inthe test element, and the reaction of sample and dissolved reagentresults in a change of a measurement variable, which can be measured onthe test element itself. Above all, optically analyzable (in particularcolorimetric) analysis systems are typical in this class, in which themeasurement variable is a color change or other optically measurablevariable. Electrochemical systems are also typical in this class, inwhich an electrical measurement variable characteristic for theanalysis, in particular an electrical current upon application of adefined voltage, can be measured in a measuring zone of the test elementusing electrodes provided in the measuring zone.

The analysis instruments of the dry-chemical analysis systems areusually compact, and some of them are portable and battery-operated. Thesystems are used for decentralized analysis, for example, at residentphysicians, on the wards of the hospitals, and in so-called “homemonitoring” during the monitoring of medical-analytic parameters by thepatient himself (in particular blood glucose analysis by diabetics orcoagulation status by warfarin patients).

In wet analysis systems, the high-performance analysis instruments allowthe performance of more complex multistep reaction sequences (“testprotocols”). For example, immunochemical analyses often require amultistep reaction sequence, in which a “bound/free separation”(hereafter “b/f separation”), i.e., a separation of a bound phase and afree phase, is necessary. According to one test protocol, for example,the probe can first be transported through a porous solid matrix, whichcontains a specific binding reagent for the analyte. A marking reagentcan subsequently be caused to flow through the porous matrix, to markthe bound analyte and allow its detection. To achieve precise analysis,a washing step must be performed, in which unbound marking reagent iscompletely removed. Numerous test protocols are known for determiningmanifold analytes, which differ in manifold ways, but which share thefeature that they require complex handling having multiple reactionsteps, in particular also a b/f separation possibly being necessary.

Test strips and similar analysis elements normally do not allowcontrolled multistep reaction sequences. Test elements similar to teststrips are known, which allow further functions, such as the separationof red blood cells from whole blood, in addition to supplying reagentsin dried form. However, they normally do not allow precise control ofthe time sequence of individual reaction steps. Wet-chemical laboratorysystems offer these capabilities, but are too large, too costly, and toocomplex to handle for many applications.

To close these gaps, analysis systems have been suggested which operateusing test elements which are implemented in such a manner that at leastone externally controlled (i.e., using an element outside the testelement itself) liquid transport step occurs therein (“controllable testelements”). The external control can be based on the application ofpressure differences (overpressure or low-pressure) or on the change offorce actions (e.g., change of the action direction of gravity byattitude change of the test element or by acceleration forces). Theexternal control is especially frequently performed by centrifugalforces, which act on a rotating test element as a function of thevelocity of the rotation.

Analysis systems having controllable test elements are known andtypically have a housing, which comprises a dimensionally-stable plasticmaterial, and a sample analysis channel enclosed by the housing, whichoften comprises a sequence of multiple channel sections and chambersexpanded in comparison to the channel sections lying between them. Thestructure of the sample analysis channel having its channel sections andchambers is defined by profiling of the plastic parts. This profiling isable to be generated by injection molding techniques or hot stamping.Microstructures, which are generated by lithography methods, areincreasingly being used more recently, however.

Analysis systems having controllable test elements allow theminiaturization of tests which have only been able to be performed usinglarge laboratory systems. In addition, they allow the parallelization ofprocedures by repeated application of identical structures for theparallel processing of similar analyses from one sample and/or identicalanalyses from different samples. It is a further advantage that the testelements can typically be produced using established production methodsand that they can also be measured and analyzed using known analysismethods. Known methods and products can also be employed in the chemicaland biochemical components of such test elements.

In spite of these advantages, there is a further need for improvement.In particular, analysis systems which operate using controllable testelements are still too large. The most compact dimensions possible areof great practical significance for many intended applications.

U.S. Pat. No. 8,114,351 B2 discloses an analysis system for the analysisof a body fluid sample for an analyte. The analysis system provides atest element and an analysis instrument having a dosing station and ameasurement station. The test element has a housing an (at least) onesample analysis channel enclosed by the housing. The test element isrotatable around an axis of rotation which extends through the testelement.

U.S. Pat. No. 8,470,588 B2 discloses a test element and a method fordetecting an analyte. The test element is essentially disk shaped andflat, and can be rotated about a preferably central axis which isperpendicular to the plane of the disk shaped test element.

Kim, Tae-Hyeong, et al. “Flow-enhanced electrochemical immunosensors oncentrifugal microfluidic platforms.” Lab on a Chip 13.18 (2013):3747-3754, doi:10.1039/c3lc50374g, (hereafter “Kim et. al.”) discloses afully integrated centrifugal microfluidic device with features fortarget antigen capture from biological samples, via a bead-basedenzyme-linked immune-sorbent assay, and flow-enhanced electrochemicaldetection. This is integrated into a Centrifugal microfluidic discs,also known as “lab-on-a-disc” or microfluidic CDs.

Martinez-Duarte, Rodrigo, et al. “The integration of 3D carbon-electrodedielectrophoresis on a CD-like centrifugal microfluidic platform.” Labon a Chip 10.8 (2010): 1030-1043, doi:10.1039/B925456K, (hereafter“Martinez-Duarte et. al.”) discloses a dielectrophoresis (DEP)-assistedfilter with a compact disk (CD)-based centrifugal platform. 3D carbonelectrodes are fabricated using the C-MEMS technique and are used toimplement a DEP-enabled active filter to trap particles of interest.

European patent application publication EP 2 302 396 A1 discloses ananalyzing device includes: an operation cavity that is adjacent to afirst reserving cavity retaining a sample liquid, in a circumferentialdirection of rotational driving; a connecting section provided on a sidewall of the first reserving cavity to suck the sample liquid by acapillary force and transfer the sample liquid to the operation cavity;and second reserving cavities that are disposed outside the operationcavity in the circumferential direction of the rotational driving andcommunicate with the outermost position of the operation cavity througha connecting passage. The connecting section is circumferentiallyextended farther than the liquid level of the sample liquid retained inthe first reserving cavity.

United States patent application publication US 2009/0246082 disclosesan analysis device comprising a separation chamber for separating asample solution into a solution component and a solid component, aholding channel for holding a predetermined amount of the separatedsolid component, a mixing chamber connected to the holding channel, anoverflow channel connected between the holding channel and theseparation chamber, a sample overflow chamber into which the samplesolution remaining in the separation chamber is discharged, and a jointchannel connecting the separation chamber and the sample overflowchamber. After the separated solution component fills the overflowchannel with priority by a capillary force, the separated solidcomponent is transferred to the holding channel via the overflowchannel, and a predetermined amount of the solid component is measured.The solid component in the holding channel is transferred to the mixingchamber by a centrifugal force, and simultaneously, the sample solutionremaining in the separation chamber is discharged to the sample overflowchamber by the siphon effect of the joint channel.

SUMMARY

A method of performing a measurement of a processed biological sample, acartridge and an automatic analyzer are disclosed in the independentclaims. Additional embodiments are given in the dependent claims.

In one aspect the invention, an embodiment provides for a method ofperforming a measurement of a processed biological sample using acartridge.

A cartridge as used here encompasses a test element for processing thebiological sample into a processed biological sample. The cartridge mayinclude structures or components which enable a measurement to beperformed on the biological sample. A cartridge is a test element as isdefined and explained in U.S. Pat. Nos. 8,114,351 B2 and 8,470,588 B2. Acartridge as used herein may also be referred to as a Centrifugalmicrofluidic disc, also known as “lab-on-a-disc” or a microfluidic CD.

A biological sample as used herein encompasses also any chemical productderived, copied, replicated, or reproduced from a sample taken from anorganism.

The cartridge is operable for being spun around a rotational axis. Thecartridge comprises a fluid chamber for receiving a fluid. In variouscontexts receiving the fluid may have different meaning. In oneinterpretation receiving the fluid may for example be receiving a fluidvia a pipette or other dispenser. In other situations the receiving ofthe fluid may be from opening a reservoir within the cartridge. Thecartridge further comprises an aliquoting chamber. The cartridge furthercomprises a first duct connecting the fluid chamber and the aliquotingchamber. The cartridge further comprises a metering chamber. Themetering chamber is operable for causing fluid to fill the meteringchamber using capillary action.

Capillary action as used herein may also refer to capillarity, capillarymotion, or wicking, or capillary force. Capillary action is the abilityof a liquid to flow in narrow spaces without the assistance of externalforces like gravity or centrifugal forces.

Capillary action is caused by intermolecular forces between the liquidand adjacent solid surfaces. Adhesive forces between the liquid and theadjacent solid surfaces can be used to counteract gravity or otherexternal forces. In some cases the capillary action can be increased bydecreasing the distance between adjacent solid surfaces.

The cartridge further comprises a second duct connecting the meteringchamber with the aliquoting chamber. The second duct comprises a ductentrance in the aliquoting chamber. The second duct further comprises aduct exit in the metering chamber. The duct exit is closer to therotational axis than the duct entrance. The second duct is operable forcausing fluid flow to flow into the metering chamber using capillaryaction. The cartridge further comprises a downstream fluidic element.The downstream fluidic element is connected to the metering chamber viaa valve. The downstream fluidic element is downstream in the sense thatfluid flows from the metering chamber to the downstream fluidic element.

The cartridge further comprises a fluidic structure for processing abiological sample into the processed biological sample. The fluidicstructure comprises the downstream fluidic element. The fluidicstructure comprises the downstream fluidic element. The downstreamfluidic element is fluidically connected to the fluidic structure. Thedownstream fluidic element may be considered to be a component or a partof the fluidic structure. The fluidic structure comprises a measurementstructure for enabling measurement of the processed biological sample.The fluidic structure is configured for receiving the biological sample.For instance the cartridge may have an entrance receptacle adapted forreceiving the biological sample.

The method comprises the step of placing the biological sample into thefluidic structure. The method further comprises the step of controllingthe rotational rate of the cartridge to process the biological sampleinto the processed biological sample using the fluidic structure. Bycontrolling the rotational rate and the duration at different rotationalrates the disc or cartridge can be used to process the biological sampleinto the processed biological sample. The method further comprises thestep of filling the fluid chamber with the fluid. In differentembodiments this may be achieved in different ways, for example areservoir within the cartridge may be opened or an external source maybe used to dispense fluid into the fluid chamber. The method furthercomprises the step of controlling the rotational rate of the cartridgeto transport the fluid from the fluid chamber to the aliquoting chambervia the first duct. In different embodiments this may be achieved indifferent ways, for instance in some examples the fluid chamber could becloser to the axis of rotation than the aliquoting chamber. In thiscase, by increasing the rotational rate the fluid may be forced throughthe first duct using a centrifugal force. In other examples the firstduct may for instance be a siphon. The siphon for example may causefluid to flow automatically by using capillary action and centrifugalforces. In this case reducing the rotational rate of the cartridge maycause fluid to fill the siphon and an increase of the rotational ratemay cause the fluid to flow from the fluid chamber to the aliquotingchamber.

The method further comprises decreasing the rotational rate of thecartridge to permit the fluid in the reservoir to flow into the secondduct and to fill the metering chamber a first time. Capillary forcescause the fluid to flow from the aliquoting chamber to the second ductand then to the metering chamber. The spinning of the cartridge with thecentrifugal force may be used to counteract this capillary force. Whenthe rotational rate of the cartridge is slowed down this then allows thecapillary action to draw the fluid into the metering chamber. Also theact of decreasing the rotational rate of the cartridge may cause forceson the fluid which cause the fluid to be forced into the meteringchamber. The method further comprises the step of increasing therotational rate of the cartridge to transfer a first part of the fluidfrom the metering chamber through the valve and to transfer a firstremaining part back to the aliquoting chamber.

The method further comprises the step of decreasing the rotational rateof the cartridge to permit the fluid in the reservoir to flow into thesecond duct and to fill the metering chamber a second time. The methodfurther comprises the step of increasing the rotational rate of thecartridge to transfer a second part of the fluid from the meteringchamber through the valve and to transfer a second remaining part backinto the aliquoting chamber. Although this is described in reproducingthe aliquoting of the fluid two times, the aliquotation of the fluid maybe repeated over and over again as long as there is enough fluid withinthe aliquoting chamber to effectively fill the metering chamber. Themethod further comprises the step of performing the measurement usingthe measurement structure and using a measurement system.

This method may have the advantage that the fluid can be transferredfrom the aliquoting chamber multiple times to the downstream fluidicelement. In some examples the measurement is an optical measurement. Themeasurement may include, but is not limited to: a photometrictransmission measurement, a measurement of the scattering of light, achemiluminescence, a fluorescence, and electrochemiluminescense (ECL)measurement.

This method may be beneficial because it may provide a means ofperforming multiple aliquotations of the fluid into the downstreamfluidic element.

In another embodiment, the metering chamber has side walls and a centralregion. The side walls taper away from the central region. Capillaryaction next to the side walls of the metering chamber is greater than inthe central region of the metering chamber.

In another embodiment the cartridge further comprises a vent which isconnected to the metering chamber. The vent is nearer to the rotationalaxis than the metering chamber. The vent for example may be connectedsuch that gas is able to enter or exit the metering chamber. This mayenable fluid to enter or exit the metering chamber.

In another embodiment, the cartridge further comprises an expansionchamber with a vent. The expansion chamber is connected to the meteringchamber. The capillary action in the metering chamber is greater thancapillary action in the expansion chamber. The expansion chamber isnearer to the rotational axis than the metering chamber.

In another embodiment the interface between the metering chamber and theexpansion chamber is formed as a capillary valve or a capillary stopvalve. In this embodiment the cross section of the metering chamberincreases step like towards the larger cross section of the expansionchamber. Thereby the fluid will not flow from the metering chamber intothe expansion chamber if no additional forces are applied.

This embodiment may have the advantage that the metering chamber fillsfirst at the side walls surrounding the central region and thereafter atthe central region. This fills the metering chamber in a predictable andcontrollable way that reduces the chances that bubbles will form oradhere.

The formation of bubbles prevent most microfluidic structures from beingused more than once for dispensing a metered amount of fluid. Forexample, the patent application US 2009/0246082 A1 teaches the use ofair holes which are positioned in various locations in an overflowchamber or channel. See for example FIGS. 3, 4, and 5 of US 2009/0246082A1. The chamber of 13 of FIG. 5(a) is essentially a siphon. Thepositioning of an air hole at the bend of a siphons as is depicted inFIG. 5(a) however does not enable the repeatable aliquoting of fluid inthe way that having a metering camber with side walls and a centralregion as described above. This potential advantage is described ingreater detail below.

Similarly an aliquoting structure described in EP 2302396 A1 enablesparallel splitting of fluid in several aliquots, but also uses a ventingstructure that only lets air in at the position nearest to therotational axis. For example see FIG. 55 of EP 2302396 A1 and theaccompanying text. The structure shown in the picture features a longcapillary channel that has to be filled by fluid. The channel featuresseveral vents and connections to downstream chambers.

In FIG. 42 of EP 2302396 A1 a siphon 215 b connects a chamber 210 b withanother chamber 209 c. Placing a vent at the point of siphon 215 bclosest to the rotational axis 107 would not enable the reliablealiquotation of the same amount of fluid every time due to the risk ofbubble formation. The structures shown in EP 2302396 has the followingdrawbacks: The refilling of such a structure for a second aliquotingstep is highly unreliable. For a second aliquoting step the capillaryhas to be filled again. As the walls of the capillary are still wet thefilling process differs from the initial filling process of the firstaliquoting step. The fluid moves significantly faster along the channelwalls than along the channels center. Due to the small channel diameterfluid progressing on one channel wall often gets in contact with fluidthe other channel wall. This causes the formation of an air bubble thatclogs the channel. This effect is significantly increased if fluids withlow surface tension (e.g. washing buffers) are aliquoted. Theprobability of air bubble formation rises with the length of thecapillary to be filled.

Experiments conducted show that long capillaries cannot be reliably usedin repetitive aliquoting steps. A structure with a single long capillaryand a vent near the bend was constructed. During the tests air bubblesclogged the vent consistently when a second aliquotation of the liquidis attempted.

The present embodiment may have a further advantage by that enablesserial and accurate aliquoting steps. A “closed” capillary with fourwalls can be completely avoided in this structure. In some examples, thefluid may pass the second duct and reach the metering chamber due to theinertia of the fluid by stopping the rotation of the disk with anegative acceleration. In some examples, the second duct does not act ascapillary. In some embodiments, the fluid may pass the second duct andreach the metering chamber due both capillary forces and forces causedby inertia. In the metering chamber the side walls may function asguidance structures at the outer walls guide the fluid due to a highercapillary action than the central region. After the side walls havefilled, the central part of the metering chamber may also fill bycapillary forces. The guidance structure features a “open” capillarystructure comprising three walls preventing air bubble formation oradhesion. The edge of the metering chamber closest to the rotationalaxis borders an expansion chamber. In some examples the central part ofthe metering chamber borders the expansion chamber over its whole width.This may avoid or reduce the risk of air bubble formation in themetering chamber which may enable the precise metering and reliablerefilling of the metering chamber for multiple subsequent aliquotationsusing the same microfluidic structure.

In addition to the potential advantages describe above, the fluidicstructure in US 2009/0246082 has the additional disadvantage whencompared to the present embodiment. The overflow chamber 15 (see FIG.5(c) of US 2009/0246082) serves to maintain and hold surplus fluid whichis in contrast to the present embodiment. Surplus fluid will becometrapped in the overflow chamber 15. In the present embodiment, the fluidin the aliquoting chamber may be able to be transferred to the meteringchamber.

In some embodiments the first part of the fluid has the same volume asthe second part of the fluid. In some embodiments the first remainingpart has the same volume as the second remaining part.

The first and second remaining parts are the part of the fluid which isin the metering chamber but is transferred back into the aliquotingchamber when the rotational rate of the cartridge is increased.

In some embodiments the rotation of the cartridge is such that thedirection of rotation passes through the aliquoting chamber first andthen the metering chamber. When this is done this way, when thecartridge is decelerated the inertia of the fluid naturally forces itinto the second duct and assists the filling of the metering chamber.

In another embodiment during performing the method the cartridge isoriented in a horizontal direction. Alternatively, the axis of rotationmay be described as being vertical.

In another embodiment the valve is a capillary valve or a capillary stopvalve.

A capillary valve or capillary stop value as used herein is a valve orstructure which uses the capillary force of a fluid to prevent fluidfrom flowing through the capillary stop valve. For example a tube with asufficiently small diameter will draw fluid into it and the capillaryforce will prevent the fluid from flowing out of the tube. For the caseof this tube the entrance and exit of the tube function as capillarystop valves. In some examples the siphon exit itself may have dimensionssmall enough (compared to the adjacent fluidic structures and chambers)that the siphon exit functions as a capillary stop.

In another embodiment the valve is a microvalve which is able to beopened and resealed. For example a paraffin-based valve with an embeddedmicro-heater may be used.

In another embodiment, the side walls of the metering chamber border theexpansion chamber.

In another embodiment, the side walls has a region closest to therotational axis wherein the region borders to and opens into theexpansion chamber.

In another embodiment, the central region of the metering chamberborders the expansion chamber.

In another embodiment, the central region has a zone closest to therotational axis. wherein the region borders to and opens into theexpansion chamber.

In another embodiment, the measuring chamber has a border between themetering chamber and the expansion chamber. The border is at least 5time longer than the width of the valve.

In another example the microvalve may be a valve based on a ferrofluidsuch as is described in Park et al in the article “MultifunctionalMicrovalves Control by Optical Illumination on Nanoheaters and ItsApplication in Centrifugal Microfluidic Devices” in Lab Chip, 2007, 7,pages 557-564.

In another embodiment the fluidic structure is a microfluidic structure.

In another embodiment the step of increasing the rotational rate of thecartridge to transfer a first part of the fluid from the meteringchamber through the valve comprises increasing the rotational rate ofthe cartridge to a first rotational rate to transfer the remaining partof the fluid back to the aliquoting chamber and increasing therotational rate of the cartridge to a second rotational rate to transferthe first part of the fluid from the metering chamber through the valve.When the cartridge is rotated at a higher rate at the first rotationalrate the centrifugal force becomes greater than any capillary forcewhich is drawing fluid into the metering chamber. Fluid is then forcedout of the metering chamber until the fluid level is equal with thelowest level of the duct exit. Increasing to the second rotational ratethen forces the fluid through the valve. In some examples the valve isopen. For example if a ferrofluid or a paraffin-based microvalve isused. This embodiment may have the benefit of increasing the accuracy ofthe fluid which is dispensed to the downstream fluidic element. As analternative to this the cartridge is simply rotated at a rate which isfast enough to force the fluid through the valve. This may result in theamount of fluid being transferred to the downstream fluidic element ifthe first and second rotational rates are used. In another alternativeif the valve is a controllably sealable or openable microvalve then thecartridge may be operated at a rotational rate to force the remainingpart of the fluid back into the aliquoting chamber. After this isaccomplished then the microvalve is opened and the rotation forces thefluid from the metering chamber into the downstream fluidic element. Asan alternative it may be possible to replace the microvalve with areusable siphon.

In some examples the fluid may be drawn into the metering chamber bycapillary forces. The decrease in the rotational rate may cause thefluid to splash or move against the connecting duct and then thecapillary forces may then fill the metering chamber. Increasing therotational rate of the cartridge to transfer the first part of the fluidmay have the effect of also cancelling any capillary forces which aredrawing fluid into the metering chamber.

In another embodiment the step of increasing the rotational rate of thecartridge to transfer a first part of the fluid from the meteringchamber through the valve comprises increasing the rotational rate ofthe cartridge to a first rotational rate to transfer the remaining partof the fluid back to the aliquoting chamber and increasing therotational rate of the cartridge to a second rotational rate to transferthe first part of the fluid from the metering chamber through the valve.When the cartridge is rotated at a higher rate at the first rotationalrate the centrifugal force becomes greater than any capillary forcewhich is drawing fluid into the metering chamber. Fluid is then forcedout of the metering chamber until the fluid level is equal with thelowest level of the duct exit. Increasing to the second rotational ratethen forces the fluid through the valve. In some examples the valve isopen.

In another embodiment, a ferrofluid or a paraffin-based microvalve isused. This embodiment may have the benefit of increasing the accuracy ofthe fluid which is dispensed to the downstream fluidic element. As analternative to this the cartridge is simply rotated at a rate which isfast enough to force the fluid through the valve. This may result in theamount of fluid being transferred to the downstream fluidic element ifthe first and second rotational rates are used. In another alternativeif the valve is a controllably sealable or openable microvalve then thecartridge may be operated at a rotational rate to force the remainingpart of the fluid back into the aliquoting chamber. After this isaccomplished then the microvalve is opened and the rotation forces thefluid from the metering chamber into the downstream fluidic element.

In another embodiment the step of increasing the rotational rate of thecartridge to transfer a second part of the fluid from the meteringchamber through the valve comprises increasing the rotational rate ofthe cartridge to the first rotational rate to transfer the remainingpart of the fluid back to the aliquoting chamber and increasing therotational rate of the cartridge to the second rotational rate totransfer the second part of the fluid from the metering chamber throughthe valve.

In one example the aliquoting chamber has a depth of approximately 2.5mm and a width of 4.0 mm. The height in the radial direction (towardsthe axis of rotation) may be 6 mm.

In one example the metering chamber may have depth of 0.8 mm and a widthof 3.8 mm. The height without the expansion chamber may be approximately7.0 mm.

In one example the second duct has a depth of 0.5 mm and a width of 1mm. In other examples the depth of the second duct is between 0.1 mm and1 mm. In other examples, the second duct has a width between 0.1 and 1.5mm. The depth is in the direction of the axis of rotation and the widthlies in the plane perpendicular to the axis of rotation.

In another aspect the invention, an embodiment provides for a cartridgefor an automatic analyzer. The cartridge is operable for being spunaround a rotational axis. The cartridge comprises a fluid chamber forreceiving a fluid. The cartridge further comprises an aliquotingchamber. The cartridge further comprises a first duct connecting thefluid chamber and the aliquoting chamber. The cartridge furthercomprises a metering chamber operable for causing fluid to fill themetering chamber using capillary action.

The cartridge further comprises a second duct connecting the meteringchamber with the aliquoting chamber. The second duct comprises a ductentrance in the aliquoting chamber. The second duct further comprises aduct exit in the metering chamber. The duct exit is closer to therotational axis than the duct entrance. The second duct is operable foror designed such that it causes fluid to flow to the metering chamberusing capillary action. The second duct may be made operable for causingfluid flow to the metering chamber by using a characteristic dimensionwhich is small enough such that it results in capillary forces.

The cartridge further comprises a downstream fluidic element. Thedownstream fluidic element is connected to the metering chamber via avalve. The cartridge further comprises a fluidic structure forprocessing a biological sample into the processed biological sample. Thefluidic structure comprises the downstream fluidic element. Thedownstream fluidic element is fluidically connected to the fluidicstructure. The fluidic structure comprises a measurement structure forenabling measurement of the processed biological sample. The fluidicstructure is configured for receiving the biological sample.

In another embodiment the aliquoting chamber has an upper portion and alower portion. The upper portion is closer to the rotational axis thanthe lower portion. The metering chamber has an upper part. The meteringchamber has a lower part. The upper part is closer to the rotationalaxis than the lower part. The duct exit is within the upper part of themetering chamber. The duct entrance is within the lower portion of thealiquoting chamber.

In another embodiment a cross-sectional view of the second duct and thealiquoting chamber is shaped similar to a watering can.

In another embodiment the metering chamber has a metering chambersurface. The metering chamber surface is at least partially rounded. Inthis embodiment the hard corners are avoided in the metering chamber toreduce the chances that a bubble forms or adheres within the meteringchamber and to promote a complete filling of the metering chamber withfluid. It may be desirable to avoid bubbles in the metering chamberbecause bubbles change the volume of fluid that can be stored in themetering chamber. If bubbles form during the filling of the meteringchamber this may result in an inconsistent amount of fluid beingtransferred to the downstream fluidic element.

In another embodiment the metering chamber has sidewalls and a centralregion. The sidewalls taper away from the central region. Having thesidewalls taper away from the central region may result in a largercapillary action near the sidewalls than in the central region area.This may cause the sidewalls to fill first with fluid and this mayreduce the chances of bubbles forming in the metering chamber.

In other embodiments the metering chamber has sidewalls. A profile ofthe metering chamber tapers towards the sidewalls.

In another embodiment the capillary action next to the sidewalls of themetering chamber is greater than in the central region of the meteringchamber. This may result in the sidewalls filling with fluid before thecentral region.

In another embodiment the sidewalls are operable for filling with fluidbefore the central region to prevent the formation and/or adherence ofbubbles in the metering chamber.

In another embodiment the capillary action of the metering chamber isgreater than the capillary action in the second duct. This may assist infilling the metering chamber with the fluid.

In another embodiment the cartridge further comprises an expansionchamber with a vent. The expansion chamber is fluidically connected tothe metering chamber. The capillary action in the metering chamber isgreater than the capillary action in the expansion chamber. Theexpansion chamber is nearer to the rotational axis than the meteringchamber. The use of such an expansion chamber may allow air to uniformlyexit the metering chamber. This may further reduce the chances ofbubbles forming or adhering in the metering chamber.

In another embodiment the metering chamber has an upper edge or surface.The upper edge or surface is the boundary of the metering chamber thatis closer to the rotational axis than the rest of the metering chamber.In this embodiment the whole upper section or boundary of the meteringchamber may open into the expansion chamber. This may further reduce thechances of bubbles forming or adhering when filling the meteringchamber.

In another embodiment the expansion chamber is closer to the rotationalaxis than the aliquoting chamber. This may be beneficial because itreduces the chances that the expansion chamber will fill with the fluid.

In another embodiment the cartridge further comprises a reservoir filledwith the fluid. The reservoir is configured for being opened and fortransferring the fluid to the fluid chamber. The cartridge may have forexample a reservoir opening element that could be used for opening thereservoir. It may also be possible that an actuator could be used toactuate or activate the reservoir opening element. For instance anautomatic analyzer may have a device which would cause the actuation ofthe reservoir or a mechanism attached to it in order to open thereservoir allowing the fluid contained in the reservoir to be enteredinto the fluid chamber.

The reservoir may for example be sealed with a removable or pierceableseal that could for example be a thin film or a foil. For example asmall piece of metal foil or a thin film of plastic may be used as apierceable seal. The fluid chamber or another component of the cartridgemay have a piercing structure for opening the pierceable seal. Thepiercing structure may be any structure which is capable of piercing theparticular pierceable seal and for instance could be a pin, a lance, ora sharp edge. In other examples the removable seal may be able to bepeeled off to open the reservoir.

In another embodiment the fluid chamber or a fluid receiving structureconnected to the fluid chamber is configured for receiving a dosingneedle for dispensing the fluid to the fluid chamber. This for instancemay be performed manually or an automatic analyzer may have a dosingneedle which automatically dispenses fluid to the fluid chamber or thefluid receiving structure.

In another embodiment the fluid is any one of the following: adispersion, a fluid comprising nanoparticles, a fluid comprising a bloodgrouping reagent, a fluid comprising an immune reagent, a fluidcomprising an antibody, a fluid comprising an enzyme, a fluid comprisingone or more substrates for an enzymatic reaction, a fluid comprisingfluorescence emitting molecules, a fluid comprising molecules formeasuring immunochemical reactions, a fluid comprising molecules formeasuring reactions of nucleic acids, a fluid comprising a recombinantprotein, a fluid comprising virus isolate, a fluid comprising a virus, afluid comprising a biological reagent, a solvent, a diluent, a buffer, afluid comprising a protein, a fluid comprising a salt, a detergent, afluid comprising a fluid comprising a nucleic acid, a fluid comprisingan acid, a fluid comprising a base, an aqueous solution, a non-aqueoussolution, and combinations thereof.

In another embodiment the measurement structure comprises two or moreelectrodes and/or an optical measurement structure. The measurementsystem comprises a system for making an electrical measurement. Themeasurement system comprises a system for making optical measurements.

In some embodiments the optical measurement structure may be atransparent structure. The measurement system comprises an opticalmeasurement system.

In some examples optically transparent may include the near infrared andnear ultraviolet. In other examples optically transparent may excludethe near infrared or near ultraviolet.

Some examples may have both the measurement structure with thetransparent structure and also the electrodes for more complicatedtests. For example the measurement structure may be a structure formaking electrochemiluminescence measurements where electrodes cause anoptical excitation in a sample.

In other examples the measurement structure comprises two or moreelectrodes for making an electrical measurement or ECL measurement ofthe processed biological sample. For example, the measurement structuresof Martinez-Duarte et. al. or Kim et. al. may be incorporated into acartridge.

Examples may also only have electrode. For example, in anelectrochemical detection structure, an electrode may be used to measurea current caused by the result of an enzymatic reaction.

In another embodiment the cartridge further comprises an excess fluidchamber connected to the aliquoting chamber via a fluidic connection.The fluidic connection comprises a fluidic connection entrance. Thefluidic connection entrance is further away from the rotational axisthan the duct exit. This may be beneficial because it means that themaximum level of the fluid in the aliquoting chamber is below the ductexit.

In another aspect the invention, an embodiment provides for an automaticanalyzer configured for receiving a cartridge according to anembodiment. The automatic analyzer comprises a cartridge spinner, ameasurement system, and a controller configured for controlling theautomatic analyzer.

The controller is configured or programmed to control the cartridgespinner to control the rotational rate of the cartridge to process thebiological sample into the processed biological sample using the fluidicstructure. The controller is further configured or programmed to controlthe cartridge spinner to control the rotational rate of the cartridge totransport the fluid from the fluid chamber to the aliquoting chamber viathe first duct.

The controller is further configured or programmed to control thecartridge spinner to force the fluid in the reservoir to flow into thesecond duct and to fill the metering chamber a first time. Thecontroller is further configured or programmed to control the cartridgespinner to increase the rotational rate of the cartridge to transfer afirst part of the fluid from the metering chamber through the valve andto transfer a first remaining part back into the aliquoting chamber. Thecontroller is further configured or programmed to control the cartridgespinner to decrease the rotational rate of the cartridge to force thefluid in the reservoir to flow into the second duct and to fill themetering chamber a second time.

The controller is further configured or programmed to control thecartridge spinner to increase the rotational rate of the cartridge totransfer a second part of the fluid from the metering chamber throughthe valve and to transfer a second remaining part back into thealiquoting chamber. The controller is further configured or programmedto control the measurement system to perform the measurement using themeasurement structure.

It is understood that one or more of the aforementioned embodiments ofthe invention may be combined as long as the combined embodiments arenot mutually exclusive.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following embodiments of the invention are explained in greaterdetail, by way of example only, making reference to the drawings inwhich:

FIG. 1 illustrates fluidic elements for performing multiple aliquots ofa fluid;

FIG. 2 illustrates a cross sectional view of a metering chamber;

FIG. 3 illustrates an example of a cartridge that incorporates thefluidic elements of FIG. 4 illustrates part of a method of performing adispensing fluid using the fluidic elements of FIG. 1;

FIG. 5 further illustrates part of a method of performing a dispensingfluid using the fluidic elements of FIG. 1;

FIG. 6 further illustrates part of a method of performing a dispensingfluid using the fluidic elements of FIG. 1;

FIG. 7 further illustrates part of a method of performing a dispensingfluid using the fluidic elements of FIG. 1;

FIG. 8 further illustrates part of a method of performing a dispensingfluid using the fluidic elements of FIG. 1;

FIG. 9 further illustrates part of a method of performing a dispensingfluid using the fluidic elements of FIG. 1;

FIG. 10 further illustrates part of a method of performing a dispensingfluid using the fluidic elements of FIG. 1;

FIG. 11 illustrates an example of an automatic analyzer; and

FIG. 12 shows a flow chart which illustrates a method of operating theautomatic analyzer of FIG. 11.

DETAILED DESCRIPTION

Like numbered elements in these figures are either equivalent elementsor perform the same function. Elements which have been discussedpreviously will not necessarily be discussed in later figures if thefunction is equivalent.

For heterogeneous immunochemical assays a washing buffer is oftenrequired to perform separation or washing steps to increase testsensitivity and reproducibility. For clinical chemistry tests buffersare often required for sample dilution or biochemical reactions.According to Richtlinie der Bundesärztekammer (RiliBÄK) guidelines forPoint of Care (POC) disposables all liquid reagents have to bepre-stored on the disposable. From such pre-storage containers, thereleased fluid volume is typically released at once. If the fluid volumehas to be split into aliquots complicated space-consuming microfluidicstructures are required. This space consumption often hinders theimplementation of parallel microfluidic structure for panels intomicrofluidic disposables.

Further, valves typically used for disc format disposables like siphons,geometrical valves or hydrophobic valves can either be used one timeonly or special variants of siphons can be used several times but afluid volume in the interconnected chamber is completely transferredthrough the valve without the possibility to split the volumes intoaliquots. Therefore with state-of-the art valves it is not possible torelease a fluid volume from a pre-storage containment into amicrofluidic cavity featuring a siphon valve and split this volume intoseveral aliquots.

A disadvantage with geometrical valves is that there is no control offluids with decreased surface tension is possible. This is especiallytrue for washing buffers.

A disadvantage with using hydrophobic valves is that there no control offluids with decreased surface tension is possible. This is especiallytrue for washing buffers. Hydrophobic valves also have the disadvantagethat they can only be used once.

A disadvantage of state of the art siphons is that state of the artsiphons can only be filled once. Air bubbles remaining in the siphonafter this has been used inhibit a second filling of the siphon. Furtherthe siphons will transfer the complete fluid volume located radiallyinwards of the siphon from an upstream chamber into a downstream fluidicelement.

FIG. 1 shows a number of fluidic components 100. The fluidic components100 are part of the fluidic components that make up a disc. There is arotational axis labeled 102. Also shown in the Figure is a portion of afluid chamber 104. The fluid chamber either is designed for receivingfluid or for having a reservoir that provides fluid via a fluid chamberduct 106 that leads into the aliquoting chamber 108. In this example thealiquoting chamber 108 is well-shaped. There is a second duct 110 whichconnects the aliquoting chamber 108 with a metering chamber 112. Thesecond duct 110 has a duct entrance 114 and a duct exit 116. The ductentrance 114 leads to the aliquoting chamber 108 and the duct exit 116leads to the metering chamber 112. The duct entrance 114 is further fromthe rotational axis 102 than the duct exit 116 of the second duct.

The metering chamber 112 is connected via a tube 120 to a downstreamfluidic element 122. In this example, there is a valve 121 between thetube 120 and the downstream fluidic element 122. The valve 121 in thisexample is a capillary valve. The valve 121 could be implemented indifferent ways. In some embodiments the tube 120 could functions as thecapillary valve. In some embodiments a duct could be connected in thesame location and a controllable microvalve could be used instead. Thecontrollable microvalve could be placed between the metering chamber 112and the tube 120 or between the tube 120 and the downstream fluidicelement 122.

An expansion chamber 124 is shown as bordering on an upper edge 126 ofthe metering chamber 112. There is a vent 128 which vents the expansionchamber 124. The whole boundary between the metering chamber 112 and theexpansion chamber 124 is open. This may help reduce the chances ofbubbles forming in the metering chamber 112. In some examples theexpansion chamber 124 may have a thickness which is greater than that ofthe metering chamber 112. Capillary forces may be used then to keep thefluid in the metering chamber 112. The dashed line labeled 130 and alsoA-A shows the location of a cross-sectional view of the metering chamber112. This cross-sectional view is shown in FIG. 2. The aliquotingchamber 108 can be shown as also having a vent 128. The region aroundthe duct entrance 114 is in this embodiment funnel-shaped. It may alsobe noted that the aliquoting chamber 108 is shown as not having sharpedges. The lack of sharp edges helps to facilitate the movement of fluidfrom the aliquoting chamber 108 to the duct entrance 114 when the discis decelerated.

The aliquoting chamber 108 is also shown as having a connection to afluidic connection 134 which leads to an excess fluid chamber 132. Thefluidic connection 134 has a fluidic connection entrance 136. Thefluidic connection entrance 136 defines the maximum fluid level in thealiquoting chamber 108. The maximum fluid level in the aliquotingchamber 108 is further from the rotational axis 102 than the duct exit116. The fluidic connection 134 is connected to the excess fluid chamber132 in this example. The use of a valve or a capillary valve isoptional. The excess fluid chamber is shown as having a vent 128 and itis also connected to a failsafe chamber 140. When the fluid flows intothe excess fluid chamber 132 the failsafe chamber 140 is filled. Thefailsafe chamber 140 may be used to indicate optically if fluid hasentered the excess fluid chamber 132. For example, during use if thefailsafe chamber 140 is not filled it may indicate that the aliquotingchamber 108 was not properly filled with fluid.

FIG. 2 shows a cross-sectional view 200 of the profile A-A which islabeled 130 in FIG. 1. In this Figure the body of the cartridge 202 canbe seen. There is an opening in the body 202 for the metering chamber112. The body of the cartridge 202 in this example is fabricated byinjection molding. The body of the cartridge is assembled from a lid 208and a support structure 210.

At the far end of the metering chamber the entrance into the valve 121can be seen. The metering chamber 112 can be seen as being divided intoseveral different regions. On the edges there are two sidewalls regions204. Between the two sidewalls regions or two side regions is a centralregion 206. The sidewall 204 regions become more narrow or taper awayfrom the central region 206. This causes a narrowing in the dimensionsof the metering chamber 112 in this region. The capillary action maytherefore be higher in the sidewall regions 204 than in the centralregion 206. This may cause the metering chamber 112 to fill with fluidfirst in the sidewall region before the central region 206. This mayhave the benefit of using a number of bubbles which are formed ortrapped in the metering chamber 112 when the metering chamber 112 isfilled with fluid.

FIG. 3 shows the integration of the fluidic components 100 into acartridge 300. The cartridge 300 is flat and disc-like and is shown ashaving a rotational axis 102. There is a fluid chamber 104 which isadapted or operable for receiving a fluid. The fluid reservoir 306filled with a fluid 307 is sealed with a pierceable seal 308 in thisexample and there is a piercing element 310 on the wall of the fluidchamber 104. The fluid reservoir has a number of engaging surfaces orreservoir opening elements 312 which may be manipulated manually or byan apparatus such as an actuator which causes the pierceable seal 308 tocontact the piercing element 310. This then causes the fluid chamber 104to fill with the fluid 307. The fluid chamber 104 is shown as beingconnected to a first duct 106. The first duct 106 is connected to analiquoting chamber 108. When the disc 300 is rotated about therotational axis 102 centrifugal force forces fluid 307 through the duct106. This then causes the aliquoting chamber 108 to fill with the fluid307.

The aliquoting chamber 108 is shown as being connected to second duct110 which leads to the metering chamber 112 as is shown in FIG. 1. Inthis example the aliquoting chamber 108 is laid out in a plane-likefashion aligned with the plane of the disc. The rotational axis isperpendicular to the plane. Attached to the aliquoting chamber 108 is anexcess fluid container 132. This is an optional element.

The metering chamber 112 is shown as being connected to a downstreamfluidic element 122 via a tube 120. There is however a valve 121 locatedbetween the metering chamber 112 and the tube 120. The downstreamfluidic element 122 is part of a fluidic structure 336 for processing abiological sample into a processed biological sample.

The fluidic structure 336 comprises a number of fluidic elements 338that are connected by various ducts and siphons 340. There are also anumber of vents 342 within the fluidic structure 336. In this examplethere is an opening 346 which enables a biological sample to be placedinto the fluidic structure 336. There is also a cover lid 348 which isused to close and seal the opening 346. The fluidic structure 336 alsocomprises a measurement structure 344 which allows a measurement to bemade on the biological sample using a measurement system.

The measurement system may for instance be an optical, electrical, or acombination of the two systems for making the measurement on theprocessed biological sample.

The processing of the biological sample can be controlled by controllingthe rotational rate about the rotational axis and duration. The siphons340 are designed to be filled automatically using a capillary action.However, a sufficiently large rotational rate about the rotational axis102 will produce a centrifugal force which will oppose the capillaryaction. Thus, by controlling the rotational rate and the duration ofrotation at particular rates the processing of the biological sample canbe controlled. In a typical usage the biological sample may be placedinto the inlet 346 and the rotation rate of the system may becontrolled. Then at some point an actuator or other mechanical means isused to manipulate the reservoir opening element and causes the piercingelement 310 to pierce the pierceable seal 308. Rotation can then forcefluid into the aliquoting chamber and a variety of rotational rates maybe used to perform multiple aliquotations using the cartridge 300.

FIGS. 4-10 illustrate how the fluidic components 100 may be used toperform multiple aliquotations of fluid to the downstream fluidicelement 122.

First, in FIG. 4, fluid has been added to the fluid chamber 104. Thecartridge is then spun about the axis of rotation 102. This forces fluid307 to travel through the first duct 106 into the aliquoting chamber108. The fluid 307 then fills the aliquoting chamber 108 and thecorresponding radially outwards portion of the second duct 110 withfluid.

FIG. 5 shows the cartridge spinning at the same rate and same direction400 as was shown in FIG. 4. In FIG. 5, all the fluid has been drainedout of the fluid chamber 104. The fluid 307 can be shown as filling thesecond duct 110 and the aliquoting chamber 108 to the maximum fluidlevel 500 which is set by the fluid connection entrance 136. Excessfluid 307 can be shown as being filled into the excess fluid chamber 132and the failsafe chamber 140.

Next, in FIG. 6, the disc stops or slows its rate of rotation. Capillaryaction in the second duct 110 and the metering chamber 112 is shown asbeginning to draw fluid into the metering chamber 112. The fluid 307first fills the periphery or edge of the metering chamber 112. Thishelps preventing the formation or adhesion of bubbles within themetering chamber 112. When the cartridge is rapidly de-acceleratedinertia of the fluid 307 may also help it to enter the metering chamber112.

Next, in FIG. 7, the cartridge is shown as being still stationary or ata reduced rotation rate and the metering chamber 112 is completelyfilled with fluid 307. The cartridge or disc may still be considered tobe at rest.

FIG. 8 shows the same view as is shown in FIG. 7 except a dashed line800 has been drawn in the metering chamber 112. This line 800 in themetering chamber 112 divides the fluid in the metering chamber intoseveral parts or portions. A part of the fluid volume or the whole fluidvolume 804 radially inward (closer to axis of rotation 102) from theline 800 may flow back into the reservoir. The radially outward part(further from the axis of rotation 102) or part 802 may be transferredinto the downstream fluidic element 122. The radially inward part 804can be referred to as the remaining part of the fluid and the radiallyoutward part 802 can be referred to as the part of the fluid 802 that istransferred into the downstream fluidic element 122. The volume of thefluid 802 is the aliquot.

Next, in FIG. 9, the disc begins to accelerate and spin around in thedirection 400. The disc for instance may spin at the rate shown in FIGS.1 and 2. The disc accelerates; this causes the capillary valve 121 toopen. The remaining part of the fluid 804 was transferred back to thealiquoting chamber 108. The part of the fluid 802 is in the process ofbeing transferred to the downstream fluidic element 122. A drop of thefluid can be seen dropping from the tube 120.

Next, in FIG. 10, it can be seen that the fluid volume 802 has beencompletely transferred to the downstream fluidic element 122 and is nolonger visible in FIG. 10. The remaining part of the fluid 804 has beentransferred into the aliquoting chamber 108 and is mixed with the fluid307. The first aliquotation step is finished; the process may berepeated again from FIG. 6 and may be repeated until the fluid volume307 in the aliquoting chamber 108 is smaller than the volume of themetering chamber 112.

FIG. 11 shows an example of an automatic analyzer. The automaticanalyzer 1100 is adapted for receiving a cartridge 300. There is acartridge spinner 1102 which is operable for rotating the cartridge 300about the rotational axis 102. The cartridge spinner 1102 has a motor1104 attached to a gripper 1106 which attaches to a portion of thecartridge 1108. The cartridge 300 is shown further as having ameasurement or transparent structure 1110. The cartridge 300 can berotated such that the measurement structure 1110 goes in front of ameasurement system 1112 which can perform for example an opticalmeasurement on the processed biological sample. The actuator 1104 as wasshown previously is also shown in this figure. It can be used to open afluid reservoir(s) in the cartridge 100. In some examples the actuatormay be replaced with a dispenser with a dosing needle for filling thefluid chamber of the cartridge 300.

The actuator 1111, the cartridge spinner 1102, and the measurementsystem 1112 are shown as all being connected to a hardware interface1116 of a controller 1114. The controller 1114 contains a processor 1118in communication with the hardware interface 1116, electronic storage1120, electronic memory 1122, and a network interface 1124. Theelectronic memory 1130 has a machine executable instructions whichenables the processor 1118 to control the operation and function of theautomatic analyzer 1100. The electronic storage 1120 is shown ascontaining a measurement 1132 that was acquired when instructions 1130were executed by the processor 1118. The network interface 1124 enablesthe processor 1118 to send the measurement 1132 via network interface1126 to a laboratory information system 1128.

FIG. 12 shows a flowchart which illustrates a method of operating theautomatic analyzer 1100 of FIG. 11. First in step 1200 the commands 1130cause the processor 1118 to control the cartridge spinner to control therotation rate of the cartridge to process the biological sample into aprocessed biological sample using the fluidic structure. Next in step1202 the commands 1130 cause the processor 1118 to control the cartridgespinner 1102 to control the rotation rate of the cartridge to transportthe fluid from the fluid chamber to the aliquoting chamber via the firstduct. Next in step 1204 the instructions 1130 cause the processor 1118to control the cartridge spinner to force fluid in the reservoir to flowinto the second duct and to fill the metering chamber a first time. Nextin step 1106 execution of the instructions 1130 cause the processor 1118to control the cartridge spinner 1102 to increase the rotational rate ofthe cartridge to transfer a first part of the fluid from the meteringchamber through the valve and to transfer a first remaining part backinto the aliquoting chamber. Next in step 1208 execution of theinstructions 1130 cause the processor 1118 to control the cartridgespinner 1102 to decrease the rotational rate of the cartridge to forcefluid in the reservoir to flow into the second duct and to fill themetering chamber a second time. Next in step 1210 execution of theinstructions 1130 cause the processor to control the cartridge spinnerto increase the rotational rate of the cartridge to transfer a secondpart of the fluid from the metering chamber through the valve and totransfer a second remaining part of the fluid back into the aliquotingchamber. Finally in step 1212 execution of the instructions 1130 causethe processor 1118 to control the measurement system 1112 to perform themeasurement using the measurement structure.

LIST OF REFERENCE NUMERALS

-   -   100 fluidic components    -   102 rotational axis    -   104 fluid chamber    -   106 fluid chamber duct    -   108 aliquoting chamber    -   110 second duct    -   112 metering chamber    -   114 duct entrance    -   116 duct exit    -   120 tube    -   121 valve    -   122 downstream fluidic element    -   124 expansion chamber    -   126 upper edge    -   128 vent    -   130 profile A-A    -   132 excess fluid chamber    -   134 fluidic connection    -   136 fluidic connection entrance    -   140 fail safe chamber    -   200 cross sectional view A-A    -   202 body of cartridge    -   204 side walls    -   206 central region    -   208 lid    -   210 support structure    -   300 cartridge    -   306 fluid reservoir with fluid    -   307 fluid    -   308 pierceable seal    -   310 piercing element    -   312 engaging surface or reservoir opening element    -   336 fluidic structure    -   338 fluidic element    -   340 siphon    -   342 vent    -   344 measurement structure    -   346 opening    -   348 cover lid    -   400 arrow    -   500 maximum fluid level    -   800 dividing line    -   802 part of fluid    -   804 remaining part of fluid    -   1100 automatic analyzer    -   1102 cartridge spinner    -   1104 motor    -   1106 gripper    -   1108 portion of cartridge    -   1110 measurement structure    -   1111 actuator    -   1112 measurement system    -   1114 controller    -   1116 hardware interface    -   1118 processor    -   1120 electronic storage    -   1122 electronic memory    -   1124 network interface    -   1126 network connection    -   1128 laboratory information system    -   1130 executable instructions    -   1132 measurement    -   1200 control the rotational rate of the cartridge to process the        biological sample into the processed biological sample using the        fluidic structure;    -   1202 control the rotational rate of the cartridge to transport        the fluid from the fluid chamber to the aliquoting chamber via        the first duct;    -   1204 control the cartridge spinner to permit the fluid in the        aliquoting chamber to flow into the second duct and to fill the        metering chamber a first time;    -   1206 increase the rotational rate of the cartridge to transfer a        first part of the fluid from the metering chamber through the        valve and to transfer a first remaining part back into the        aliquoting chamber;    -   1208 decrease the rotational rate of the cartridge to permit the        fluid in the reservoir to flow into the second duct and to fill        the metering chamber a second time;    -   1210 increase the rotational rate of the cartridge to transfer a        second part of the fluid from the metering chamber through the        valve and to transfer a second remaining part back into the        aliquoting chamber; and    -   1212 perform the measurement using the measurement structure.

What is claimed is:
 1. A method of performing a measurement of aprocessed biological sample using a cartridge, wherein the cartridge isoperable for being spun around a rotational axis, wherein the cartridgecomprises: a fluid chamber for receiving a fluid; an aliquoting chamber;a first duct connecting the fluid chamber and the aliquoting chamber; ametering chamber, wherein the metering chamber is operable for causingfluid to fill the metering chamber using capillary action, wherein themetering chamber has side wall regions and a central region, wherein theside wall regions are narrower than the central region in a crosssectional view of the metering chamber, wherein capillary action next tothe side wall regions of the metering chamber is greater than in thecentral region of the metering chamber; a second duct connecting themetering chamber with the aliquoting chamber, wherein the second ductcomprises a duct entrance in the aliquoting chamber, wherein the secondduct further comprises a duct exit in the metering chamber, wherein theduct exit is closer to the rotational axis than the duct entrance,wherein the second duct is operable for causing fluid to flow to themetering chamber using capillary action; a downstream fluidic element,wherein the downstream fluidic element is connected to the meteringchamber via a valve; a fluidic structure for processing a biologicalsample into the processed biological sample, wherein the fluidicstructure comprises the downstream fluidic element, wherein thedownstream fluidic element is fluidically connected to the fluidicstructure, wherein the fluidic structure comprises a measurementstructure for enabling measurement of the processed biological sample,wherein the fluidic structure is configured for receiving the biologicalsample; a vent connected to the metering chamber, wherein the vent isnearer to the rotational axis than the metering chamber, wherein themethod comprises the steps of: placing the biological sample into thefluidic structure; controlling the rotational rate of the cartridge toprocess the biological sample into the processed biological sample usingthe fluidic structure; filling the fluid chamber with the fluid;controlling the rotational rate of the cartridge to transport the fluidfrom the fluid chamber to the aliquoting chamber via the first duct;decreasing the rotational rate of the cartridge to permit the fluid inthe aliquoting chamber to flow into the second duct and to fill themetering chamber a first time; increasing the rotational rate of thecartridge to transfer a first part of the fluid from the meteringchamber through the valve and to transfer a first remaining part backinto the aliquoting chamber; decreasing the rotational rate of thecartridge to permit the fluid in the reservoir to flow into the secondduct and to fill the metering chamber a second time; increasing therotational rate of the cartridge to transfer a second part of the fluidfrom the metering chamber through the valve and to transfer a secondremaining part back into the aliquoting chamber; and performing themeasurement using the measurement structure and using a measurementsystem.
 2. The method of claim 1, wherein the step of increasing therotational rate of the cartridge to transfer the first part of the fluidfrom the metering chamber through the valve comprises increasing therotational rate of the cartridge to a first rotational rate to transferthe first remaining part of the fluid back to the aliquoting chamber andincreasing the rotational rate of the cartridge to a second rotationalrate to transfer the first part of the fluid from the metering chamberthrough the valve; and/or wherein the step of increasing the rotationalrate of the cartridge to transfer a second part of the fluid from themetering chamber through the valve comprises increasing the rotationalrate of the cartridge to the first rotational rate to transfer thesecond remaining part of the fluid back to the aliquoting chamber andincreasing the rotational rate of the cartridge to the second rotationalrate to transfer the second part of the fluid from the metering chamberthrough the valve.
 3. The method of claim 1, wherein the side wallregions are operable for filling with fluid before the central region toprevent the formation and/or adherence of bubbles in the meteringchamber.
 4. The method of claim 1, wherein the aliquoting chamber has anupper portion and a lower portion, wherein the upper portion is closerto the rotational axis than the lower portion, wherein the meteringchamber has an upper part, wherein the metering chamber has a lowerpart, wherein the upper part is closer to the rotational axis than thelower part, wherein the duct exit is within the upper part of themetering chamber, and wherein the duct entrance is within the lowerportion of the aliquoting chamber.
 5. The method of claim 1, wherein themetering chamber has a metering chamber surface, wherein the meteringchamber surface is rounded.
 6. The method of claim 1, wherein thecapillary action in the metering chamber is greater than the capillaryaction in the second duct.
 7. A cartridge for an automatic analyzer,wherein the cartridge is operable for being spun around a rotationalaxis, wherein the cartridge comprises: a fluid chamber for receiving afluid; an aliquoting chamber; a first duct connecting the fluid chamberand the aliquoting chamber; a metering chamber operable for causingfluid to fill the metering chamber using capillary action, wherein themetering chamber has side wall regions and a central region, wherein theside wall regions are narrower than the central region in a crosssectional view, wherein capillary action next to the side wall regionsof the metering chamber is greater than in the central region of themetering chamber; a second duct connecting the metering chamber with thealiquoting chamber, wherein the second duct comprises a duct entrance inthe aliquoting chamber, wherein the second duct further comprises a ductexit in the metering chamber, wherein the duct exit is closer to therotational axis than the duct entrance, wherein the second duct isoperable for causing fluid to flow to the metering chamber usingcapillary action; a downstream fluidic element, wherein the downstreamfluidic element is connected to the metering chamber via a valve; afluidic structure for processing a biological sample into the processedbiological sample, wherein the fluidic structure comprises thedownstream fluidic element, wherein the downstream fluidic element isfluidically connected to the fluidic structure, wherein the fluidicstructure comprises a measurement structure for enabling measurement ofthe processed biological sample, wherein the fluidic structure isconfigured for receiving the biological sample; and a vent, wherein thevent is connected to the metering chamber, wherein the vent is nearer tothe rotational axis than the metering chamber.
 8. The cartridge of claim7, wherein the aliquoting chamber has an upper portion and a lowerportion, wherein the upper portion is closer to the rotational axis thanthe lower portion, wherein the metering chamber has an upper part,wherein the metering chamber has a lower part, wherein the upper part iscloser to the rotational axis than the lower part, wherein the duct exitis within the upper part of the metering chamber, and wherein the ductentrance is within the lower portion of the aliquoting chamber.
 9. Thecartridge of claim 7, wherein the metering chamber has a meteringchamber surface, wherein the metering chamber surface is rounded. 10.The cartridge of claim 7, wherein the capillary action in the meteringchamber is greater than the capillary action in the second duct.
 11. Thecartridge of claim 7, wherein the cartridge further comprises anexpansion chamber, wherein the vent is within the expansion chamber,wherein the expansion chamber is connected to the metering chamber,wherein capillary action in the metering chamber is greater thancapillary action in the expansion chamber, wherein the expansion chamberis nearer to the rotational axis than the metering chamber.
 12. Thecartridge of claim 11, wherein the expansion chamber is closer to therotational axis than the aliquoting chamber.
 13. The cartridge of claim7, wherein the measurement structure comprises two or more electrodesand/or an optical measurement structure.
 14. The cartridge of claim 7,wherein the cartridge further comprises a reservoir filled with thefluid, and wherein the reservoir is configured for being opened and fortransferring the fluid to the fluid chamber.
 15. The cartridge of claim14, wherein the fluid is any one of the following: a dispersion, a fluidcomprising nanoparticles, a fluid comprising a blood grouping reagent, afluid comprising an immune reagent, a fluid comprising an antibody, afluid comprising an enzyme, a fluid comprising one or more substratesfor an enzymatic reaction, a fluid comprising fluorescence emittingmolecules, a fluid comprising molecules for measuring immunochemicalreactions, a fluid comprising molecules for measuring reactions ofnucleic acids, a fluid comprising a recombinant protein, a fluidcomprising virus isolate, a fluid comprising a virus, a fluid comprisinga biological reagent, a solvent, a diluent, a buffer, a fluid comprisinga protein, a fluid comprising a salt, a detergent, a fluid comprising afluid comprising a nucleic acid, a fluid comprising an acid, a fluidcomprising a base, an aqueous solution, a non-aqueous solution, andcombinations thereof.
 16. The cartridge of claim 7, wherein thecartridge further comprises an excess fluid chamber connected to thealiquoting chamber via a fluidic connection, wherein the fluidicconnection comprises a fluidic connection entrance, and wherein fluidicconnection entrance is further away from the rotational axis than theduct exit of the second duct.
 17. Automatic analyzer configured forreceiving a cartridge according to claim 7, wherein the automaticanalyzer comprises a cartridge spinner, a measurement system, and acontroller configured to control the automatic analyzer, wherein thecontroller is configured to: control the cartridge spinner to controlthe rotational rate of the cartridge to process the biological sampleinto the processed biological sample using the fluidic structure;control the cartridge spinner to control the rotational rate of thecartridge to transport the fluid from the fluid chamber to thealiquoting chamber via the first duct; control the cartridge spinner topermit the fluid in the reservoir to flow into the second duct and tofill the metering chamber a first time; control the cartridge spinner toincreasing the rotational rate of the cartridge to transfer a first partof the fluid from the metering chamber through the valve and to transfera first remaining part back into the aliquoting chamber; control thecartridge spinner to decrease the rotational rate of the cartridge topermit the fluid in the reservoir to flow into the second duct and tofill the metering chamber a second time; control the cartridge spinnerto increasing the rotational rate of the cartridge to transfer a secondpart of the fluid from the metering chamber through the valve and totransfer a second remaining part back into the aliquoting chamber; andcontrol the measurement system to perform the measurement using themeasurement structure.